In the manufacture of various types of garments, it is sometimes desirable to provide a pocket at a location on the garment where no seam exists. Such a pocket is commonly referred to as a "set-in" pocket. For example, in the manufacture of tubular knit pants, a seam is created down the front and back of the pants, but the sides of the pants, where pockets are typically provided, are seamless. Other types of garments requiring a set-in pocket may be hooded sweat shirts, sweat pants, placket front shirts, and slacks.
One method for sewing a pocket at a seamless position on a garment is to overlay a pocket piece of material onto the garment material, sew two parallel rows of stitches through both of the materials, and cut the two overlying materials between the two rows of stitches. The resulting stitched and cut overlying materials can then be formed into a pocket with a few additional sewing operations.
In the past, the cutting step of such a method was typically a manual operation, and as a result usually required the production of low-cost garments with set-in pockets to be carried out in third world countries where labor is cheap. However, cloth cutting attachments for double needle sewing machines have been devised that, in conjunction with the sewing needles, automatically stitch and cut the overlying pieces between the lines of stitching in one operation.
The cloth cutter attachment includes a cutter blade that is carried on the reciprocating needle bar of the sewing machine and is movable so as to first cut the cloth ahead of the stitches being formed at the beginning of the lines of stitching and later is moved to cut the cloth behind the stitches being formed at the ends of the lines of stitching. The cloth cutter attachment also includes a non-reciprocating lever for changing the position of the cutter. As a result, the manufacture of the rather complex movable cutter that must move with the sewing needles and also must shift to be ahead of and behind the needles was heavy and expensive and the operation of the system was relatively slow. Therefore, the garments on which the prior art devices are used usually are relatively expensive.
The provision of an actuator means, which rides on the reciprocating needle bar mount to shift the cutter blade, was later developed and was determined to create control problems due to vibrations caused by the high rate of reciprocation of the needle bar.